<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta
    http-equiv="X-UA-Compatible"
    content="IE=edge"
  >
  <meta
    name="viewport"
    content="width=device-width, initial-scale=1.0"
  >
  <title>Document</title>
  <style>
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
      color: rgb(242, 8, 20);
    }

    div {
      color: red;
    }

    #name {
      color: blue;
    }

    .name {
      color: black;
    }

    .border-box {
      box-sizing: border-box;
      width: 200px;
      height: 200px;
      padding: 20px;
      border: 20px solid red;
      background: yellow;
    }

    .content-box {
      box-sizing: content-box;
      width: 100px;
      height: 100px;
      margin: 50px;
      padding: 50px;
      border: 20px solid #ddd;
    }
  </style>
</head>

<body>
  <div
    id="name"
    class="name v"
  >123</div>
  <span>32423423</span>

  <div class="border-box">2</div>
  <div class="content-box"></div>
</body>

</html>